1. Field of the Invention
This invention relates generally to electronic printer/copiers having memory for storing reproduction jobs, or portions of jobs, and more particularly to security of such printer/copiers to inhibit unauthorized access to such jobs.
2. Description of the Prior Art
Electronic printer/copiers and similar devices generally store job data in memory before reproduction. Conventionally, the memory consists of dynamic random access memory (DRAM). In some instances, the amount of data can be substantial; even to the degree of storing an entire multiple page reproduction job.
The image data stored in memory remains resident in the memory after that image has been reproduced, even though the pointers to that data have been lost. This presents a security problem if the printer/copier is unattended after a confidential job has been run and before the memory locations are overwritten by the next job. A non-authorized person could access the memory and obtain a print out of the image data therein.
One solution is to "clear" the memory by writing to every location in memory immediately following the reproduction job. However, this requires a substantial amount of time in which the printer/copier would be disabled. For example, a thirty two Megabyte memory would require and excess of eight minutes to clear by writing to every location.